Simple C++-QObject with QML children (using the "data" property only)

childrencontainer.cpp

#include "childrencontainer.h"

ChildrenContainer::ChildrenContainer(QObject *parent) : QObject(parent)
{

}

QQmlListProperty<QObject> ChildrenContainer::data()
{
    return QQmlListProperty<QObject>(
        this, this,
        &ChildrenContainer::dataAppend,
        &ChildrenContainer::dataCount,
        &ChildrenContainer::dataAt,
        &ChildrenContainer::dataClear
    );
}

void ChildrenContainer::dataAppend(QObject *object)
{
    _children.append(object);
}

int ChildrenContainer::dataCount() const
{
    return _children.count();
}

QObject *ChildrenContainer::dataAt(int idx) const
{
    return _children.at(idx);
}

void ChildrenContainer::dataClear()
{
    _children.clear();
}

void ChildrenContainer::dataAppend(QQmlListProperty<QObject> *list, QObject *object)
{
    reinterpret_cast<ChildrenContainer*>(list->data)->dataAppend(object);
}

int ChildrenContainer::dataCount(QQmlListProperty<QObject> *list)
{
    return reinterpret_cast<ChildrenContainer*>(list->data)->dataCount();
}

QObject *ChildrenContainer::dataAt(QQmlListProperty<QObject> *list, int idx)
{
    return reinterpret_cast<ChildrenContainer*>(list->data)->dataAt(idx);
}

void ChildrenContainer::dataClear(QQmlListProperty<QObject> *list)
{
    reinterpret_cast<ChildrenContainer*>(list->data)->dataClear();
}

childrencontainer.h

#ifndef CHILDRENCONTAINER_H
#define CHILDRENCONTAINER_H

#include <QObject>
#include <QQmlListProperty>

class ChildrenContainer : public QObject
{
    Q_OBJECT

    Q_PROPERTY(QQmlListProperty<QObject> data READ data)
    Q_CLASSINFO("DefaultProperty", "data")
public:
    explicit ChildrenContainer(QObject *parent = nullptr);

    QQmlListProperty<QObject> data();

    void dataAppend(QObject* object);
    int dataCount() const;
    QObject* dataAt(int idx) const;
    void dataClear();

private: // members
    QList<QObject*> _children;

private: // methods
    static void dataAppend(QQmlListProperty<QObject>* list, QObject* object);
    static int dataCount(QQmlListProperty<QObject>* list);
    static QObject* dataAt(QQmlListProperty<QObject>* list, int idx);
    static void dataClear(QQmlListProperty<QObject>* list);
};

#endif // CHILDRENCONTAINER_H